CHICAGO (AP) — A visitor to Chicago's Cook County Jail was trapped inside for about 30 hours over the July Fourth weekend.

According to reports a man was in the jail's maximum security division visiting his son when he went into a room that wasn't being used. The room's door was propped open by contractors installing cameras.

Jail Executive Director Cara Smith says the door closed, locking the visitor inside from about 6 p.m. Saturday until 1 a.m. Monday.

Smith says the man pounded on the door, but its thickness muffled his efforts. The man drew attention to his plight by breaking a fire sprinkler head to summon the fire department.

Smith says investigators are trying to determine why the door was open and why no one noticed the man hadn't checked out.

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